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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * The Universal Permissive License (UPL), Version 1.0
 *
 * Subject to the condition set forth below, permission is hereby granted to any
 * person obtaining a copy of this software, associated documentation and/or
 * data (collectively the "Software"), free of charge and under any and all
 * copyright rights in the Software, and any and all patent rights owned or
 * freely licensable by each licensor hereunder covering either (i) the
 * unmodified Software as contributed to or provided by such licensor, or (ii)
 * the Larger Works (as defined below), to deal in both
 *
 * (a) the Software, and
 *
 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
 * one is included with the Software each a "Larger Work" to which the Software
 * is contributed by such licensors),
 *
 * without restriction, including without limitation the rights to copy, create
 * derivative works of, display, perform, and distribute the Software and make,
 * use, sell, offer for sale, import, export, have made, and have sold the
 * Software and the Larger Work(s), and to sublicense the foregoing rights on
 * either these or other terms.
 *
 * This license is subject to the following condition:
 *
 * The above copyright notice and either this complete permission notice or at a
 * minimum a reference to the UPL must be included in all copies or substantial
 * portions of the Software.
 *
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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package com.oracle.truffle.dsl.processor;

import java.lang.annotation.Annotation;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import javax.annotation.processing.AbstractProcessor;
import javax.annotation.processing.ProcessingEnvironment;
import javax.annotation.processing.RoundEnvironment;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import javax.tools.Diagnostic.Kind;

import com.oracle.truffle.api.dsl.Executed;
import com.oracle.truffle.api.dsl.Fallback;
import com.oracle.truffle.api.dsl.NodeChild;
import com.oracle.truffle.api.dsl.NodeChildren;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.dsl.TypeSystem;
import com.oracle.truffle.api.dsl.TypeSystemReference;
import com.oracle.truffle.dsl.processor.ProcessorContext.ProcessCallback;
import com.oracle.truffle.dsl.processor.generator.NodeCodeGenerator;
import com.oracle.truffle.dsl.processor.generator.TypeSystemCodeGenerator;
import com.oracle.truffle.dsl.processor.java.ElementUtils;
import com.oracle.truffle.dsl.processor.parser.AbstractParser;
import com.oracle.truffle.dsl.processor.parser.NodeParser;
import com.oracle.truffle.dsl.processor.parser.TypeSystemParser;

/**
 * THIS IS NOT PUBLIC API.
 */
public class TruffleProcessor extends AbstractProcessor implements ProcessCallback {

    private List<AnnotationProcessor<?>> generators;

    @Override
    public SourceVersion getSupportedSourceVersion() {
        return SourceVersion.latest();
    }

    @Override
    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
        if (!roundEnv.processingOver()) {
            processImpl(roundEnv);
        }
        return false;
    }

    private void processImpl(RoundEnvironment env) {
        // TODO run verifications that other annotations are not processed out of scope of the
        // operation or type lattice.
        try {
            ProcessorContext.setThreadLocalInstance(new ProcessorContext(processingEnv, this));
            for (AnnotationProcessor<?> generator : getGenerators()) {
                AbstractParser<?> parser = generator.getParser();
                if (parser.getAnnotationType() != null) {
                    for (Element e : env.getElementsAnnotatedWith(parser.getAnnotationType())) {
                        processElement(generator, e, false);
                    }
                }

                for (Class<? extends Annotation> annotationType : parser.getTypeDelegatedAnnotationTypes()) {
                    for (Element e : env.getElementsAnnotatedWith(annotationType)) {
                        TypeElement processedType;
                        if (parser.isDelegateToRootDeclaredType()) {
                            processedType = ElementUtils.findRootEnclosingType(e);
                        } else {
                            processedType = ElementUtils.findNearestEnclosingType(e);
                        }
                        processElement(generator, processedType, false);
                    }
                }

            }
        } finally {
            ProcessorContext.setThreadLocalInstance(null);
        }
    }

    private static void processElement(AnnotationProcessor<?> generator, Element e, boolean callback) {
        try {
            generator.process(e, callback);
        } catch (Throwable e1) {
            handleThrowable(generator, e1, e);
        }
    }

    private static void handleThrowable(AnnotationProcessor<?> generator, Throwable t, Element e) {
        String message = "Uncaught error in " + generator.getClass().getSimpleName() + " while processing " + e + " ";
        ProcessorContext.getInstance().getEnvironment().getMessager().printMessage(Kind.ERROR, message + ": " + ElementUtils.printException(t), e);
    }

    @Override
    public void callback(TypeElement template) {
        for (AnnotationProcessor<?> generator : generators) {
            Class<? extends Annotation> annotationType = generator.getParser().getAnnotationType();
            if (annotationType != null) {
                Annotation annotation = template.getAnnotation(annotationType);
                if (annotation != null) {
                    processElement(generator, template, true);
                }
            }
        }
    }

    @Override
    public Set<String> getSupportedAnnotationTypes() {
        Set<String> annotations = new HashSet<>();
        addAnnotations(annotations, Arrays.asList(Fallback.class, TypeSystemReference.class,
                        Specialization.class,
                        Executed.class,
                        NodeChild.class,
                        NodeChildren.class));
        addAnnotations(annotations, Arrays.asList(TypeSystem.class));
        return annotations;
    }

    private static void addAnnotations(Set<String> annotations, List<? extends Class<? extends Annotation>> annotationClasses) {
        if (annotationClasses != null) {
            for (Class<? extends Annotation> type : annotationClasses) {
                annotations.add(type.getCanonicalName());
            }
        }
    }

    private List<AnnotationProcessor<?>> getGenerators() {
        if (generators == null && processingEnv != null) {
            generators = new ArrayList<>();
            generators.add(new AnnotationProcessor<>(new TypeSystemParser(), new TypeSystemCodeGenerator()));
            generators.add(new AnnotationProcessor<>(new NodeParser(), new NodeCodeGenerator()));
        }
        return generators;
    }

    @Override
    public synchronized void init(ProcessingEnvironment env) {
        this.processingEnv = env;
        super.init(env);
    }

}
